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Preventing and Managing Strangles

Isolation of infected horses and rigorously enforced bio-security is essential to the effective management of strangles

Taking measures to prevent, or minimise the spread of, disease is an animal health and welfare priority. Invariably the costs and disruption of planned preventative measures are significantly less than those associated with treating the disease once it takes hold.

The clinical signs of strangles and how it spreads are detailed in All About Strangles (Streptococcus equi). Taking preventative steps both at home and when out and about with your horse or pony can make a huge difference to keeping strangles at bay. On a yard, the best approach is to implement a clear, concise agreement that everyone understands and can work with.

A strangles prevention and screening policy

Your yard strangles prevention/screening policy should address:

  • The introduction of new horses to the yard.
  • Strangles testing for new horses before they arrive on the yard.
  • Horses taking part in events off-site.
  • Other horses coming onto your yard for events.
  • Horse transport.
  • Where to locate an isolation area/barn and when and how to use it.
  • Prompt, open, unambiguous and positive communication.

Biosecurity away from home

Biosecurity is covered in greater depth here on this website. Most horse owners will want to transport their horses to participate in shows, events, competitions or even just for an enjoyable hack with friends in new surroundings. Taking straightforward steps to implement effective biosecurity will reduce the risk of picking up strangles whilst away from home:

  • Don’t allow direct contact between your own horse and others.
  • Avoid touching other horses, or wash/sanitise your hands before handling others again, including your own.
  • Discourage contact between your horse and people who have been handling other horses.
  • Only use your own tack, rugs and equipment.
  • Provide your own food and forage, and carry a container of your own water.
  • Avoid using communal water sources where horses immerse their muzzles, such as troughs.
  • Avoid communal grazing areas; when resting keep horses stabled or with your vehicle.

Biosecurity when returning home

When returning home from shows and competitions, horses and ponies should ideally be treated as new arrivals and quarantined. Of course, that is not always possible, but the animals should, at the very least, be closely and regularly monitored. It is therefore important to familiarise yourself with your horse’s clinical signs and through twice daily temperature-taking, understand what the normal baseline is.

Managing and controlling strangles

Strangles has an incubation period of between 3 and 21 days. Horses become contagious just before they exhibit symptoms, so by the time a horse has nasal discharge, it may already have passed the disease on to others. Fever normally precedes infectivity by 2 to 3 days, making it the best way to catch strangles early.

Immediately you suspect strangles, contact your vet and request an urgent examination for your horse for strangles. If strangles is confirmed you should ensure movement of horses and ponies on and off the yard stops immediately. Clear signage should be placed at every access point to the premises warning of the enforced quarantine and the bio-security measures to be followed. If there are footpaths across the site, consult the relevant authority about closing them and erect warning signs. Work with your vet to implement the traffic light system – this will enable you to contain the disease effectively, even on a large yard:

Red zone(s) – strict isolation for horses exhibiting clinical signs of strangles or who have tested positive for the bacteria.

Amber zone(s) – strict isolation for horses who may have had direct or indirect contact with the sick horse at any point during the last three weeks and may be incubating the disease.

Green zone(s) – close monitoring but normal management for horses that are not thought to have been in contact with any sick or at risk horses for at least three weeks.

Care for horses in red zones

Horses with strangles usually feel very ill (although mild cases can also occur). Stable them if possible to help keep them warm, dry and encourage them to rest. The stable should be sheltered but well-ventilated (strangles is NOT an airborne disease). The disease will need to run its course once it has taken hold, but work with your vet to keep the horse comfortable, provide nursing care and help reduce the severity of their illness, as well as monitoring for complications.

  • Your vet will normally prescribe a non-steroidal anti-inflammatory medication to help with pain, fever and swelling.
  • Antibiotics may be ineffective in strangles cases – your vet will know if and when to prescribe them.
  • Provide a full, deep bed for extra comfort.
  • Soak food to make it easier to swallow and provide a raised feed bowl for a horse who has abscesses developing, then feed from the floor once abscesses have burst to encourage pus to drain.
  • Encourage the horse to eat – try adding soaked sugar beet or handfuls of fresh grass as appetisers.
  • Adding medication to food may mean neither are consumed – administer medicines separately if necessary.
  • Gently apply a warm compress at least once a day to developing abscesses to encourage them to swell and burst (this should make the horse more comfortable) but never squeeze or pierce an abscess.
  • Gently bathe a ruptured abscess to keep it clean and encourage it to drain.
  • Environmental enrichment may help a horse cope with their time in isolation – especially as they start to feel better.

Care for horses in amber zones

Monitor horses closely for any strangles symptoms. Take temperatures twice daily, at the same times each day, to give you the best chance of catching the disease early and being able to move an infected horse to the red zone before they start shedding bacteria. Isolate amber zone horses as strictly as horses in the red zone. Remember that horses normally shed bacteria for several days before they become obviously ill.

If all the horses in a well-contained amber zone show no sign of disease for three weeks after their last possible contact with an infected horse (or are tested by a vet and the results are negative) your vet may lift isolation so the area becomes designated a green zone.

Care for horses in green zones

Horses in green zones have been identified as low-risk for exposure to strangles, but they should still be monitored carefully. They need to be protected from the infection in the red zone and any possible infection in the amber zone. People allocated to care for horses in the green zone must not enter the red and amber isolation areas at all.

If absolutely necessary, due to shortage of carers, always start by caring for the horses in the green zone, then move to amber and finally to red to minimise the risk of transferring infection.

Always be guided by your vet, but it is usually safer and easier to put a whole yard into red and amber isolation as a precaution when strangles is first identified on a yard, then use mapping and monitoring to gradually release horses into green zones when you are confident they have not been at risk.

If your yard does not use a screening protocol for new arrivals, this can be an ideal opportunity to test all horses to check that there are no strangles carriers among your residents and to introduce a screening policy so that you remain carrier-free into the future.

Biosecurity after strangles

Cleaning up thoroughly after strangles is absolutely essential. The length of time strangles bacteria can survive in the environment is dependent on exposure to sunlight, temperature and moisture. Bacteria may survive for just one or two days in a hot, dry environment, but up to 34 days in cool, damp conditions and can survive for even longer in water, still being detectable in a water trough six weeks after contamination.

Barns, stables and paddocks

All areas that have been used by any horse with strangles need to be thoroughly cleaned and disinfected, with intensive scrubbing and scraping to remove dried discharge. It is advisable to clean the living area of an infected horse routinely throughout their illness.

Rubber matting in stables must be lifted, and scrubbed and disinfected on both sides.

Paddocks that may be contaminated by infected horses must be rested for at least two weeks. Rest a paddock for at least six weeks if it contains a natural water source like a pond that horses have had access to for drinking.


Strangles bacteria survive longer in water. Empty and disinfect all water tanks and buckets, making sure that water has enough neat disinfectant added to it to kill all bacteria before tipping it away and rinsing the tank or bucket thoroughly.


All equipment that has been used in an isolation area must be thoroughly cleaned and disinfected. For peace of mind when disinfecting a red zone leave items such as haynets, head collars, lead ropes, rugs etc to soak in disinfectant for at least three hours (or overnight), before being thoroughly rinsed and dried.


Horse transport is an important source of infection and the stress of travel can increase shedding rates. Any horsebox or trailer that has been used by an infected horse (including during the three weeks before they became ill) needs to be completely disinfected, including the driver’s cab and living area or towing vehicle.


Muck from infected horses should be disposed of with care as it is a high-risk source of contamination. The two main options for safe disposal are:

  1. Find a suitable field or piece of land that is away from water courses, and which is not used by horses or people for at least two months, where the muck can be spread to expose any bacteria to the elements.
  2. Store the muck as a composting heap (the heat generated will kill the bacteria) cordoned off in an out of the way corner for at least six months then dispose of as usual.

Social media and unhelpful comments

Whilst communicating openly, clearly and concisely about an outbreak is a good thing, try to avoid being drawn into unhelpful conversations online. Social media channels are important for effective communication to stakeholder groups and target audiences, but be wary of social media becoming a source of anxiety. Sometimes people decide to say that they will be focusing on caring for their horse and not posting again until the outbreak has been cleared. Alternatively, turning off comments on your posts will prevent negative responses.

Veterinary advice and expertise

Rely on your veterinary practice for support and guidance. Veterinary medical advice is evidence based and you can be sure your vet will provide sound professional advice, taking into account the facilities at your yard, the number of people available to help you and any other relevant factors. Do not be afraid to discuss the financial aspects of a strangles management plan, right at the outset.

Redwings, the horse sanctuary charity, has prepared an excellent resource on strangles in conjunction with Dr. Andrew Waller (formerly of the AHT), Jan Rogers (Horse Trust), Prof. Josh Slater (RVC), Roly Owers (Equine Disease Coalition, World Horse Welfare). The guide, which is endorsed by the British Horse Society and British Equine Veterinary Association, has been drawn upon in the preparation of this article.